I'm making a thesis proposal.. if this one gets through..it'll be my thesis

Have you tried visiting any existing center? You can ask for some statistics.

Here are some general principles to consider;
1. Itís an out-of-home placement. The Center shall contain secured and non-secured care facilities.
2. Concerns for safety and welfare of its youth. The facility shall encourage dignity, self-worth and developing responsibility. Key word is regaining self-esteem.
3. The center is a place to provide active programs in education, recreation, and counseling.
4. Provide a safe living environment for youth.
5. Provide basic needs of youth.
6. Provide an atmosphere which will develop and maintain self-respect, responsibility and concern for others.
7. The facility shall help the youth to discover and utilize resources that can help them to live successfully.
8. The center is also an opportunity for employment.

You will generally get a better response if you provide a little more information to start with. What are some of the principles you are already familiar with? Which ones interest you and which ones would you like to find out more about?

Your title "therapeutic design in a youth prison" makes me think you're asking about interior design, but then you mention New Urbanism, so I'm not quite sure about the scope of what you're looking at?

I know a little about principles of environmental psychology applied to youth detention facilities. Could you elaborate on what you mean by therapeutic design in this context, this might help you get some more input

nevermind the New Urbanism thing, I guess its not applicable to smaller projects.
the Facility I'm mentioning is for Children in Conflict with the law. I'd like to know the principles of planning a jail that doesn't like a jail but more of a detention home.

Okay well I don't know much about layout, but a couple of things I've picked up are about use of colour and materials. An underlying principle is that most of the youths will have ended up there because they've had pretty tough lives, and there's not a lot of point in 'punishing' them further by putting them in a scary, adult-type lock-up facilility. The same could be argued for adults, however because juveniles are still young, they are more impressionable and there is more chance of rehabilitation. So, rather than using a lot of grey, metal, hard surfaces, why not use some softer colours, and rather than making everything (doors, furniture etc) totally indestructible, why not accept a certain level of replacement will be required for some features or elements that may be, for example, made from wood, instead of super-tough materials.

I visited one facility that had a pool that was used for supervised fitness and recreational sessions. Using it was a privilege that could be withdrawn for misbehaviour. Rooms were locked at night but during the day the youths had some freedom to move about common areas, and the whole facility was reasonably open and well-lit.